The noise, crowding, and littering on Sundays are an externality of HK's domestic helper system.
Raising the DHs' minimum wage to at least the minimum that locals would receive, making their wages hourly with real oversight to rein in attempts at shortchanging them, requiring employers to have a separate room of a minimum size (larger than the sorts of crawlspace-with-toilet-water-hose-and-drain that I've seen) or to pay extra for live-out rent, and a couple of other measures would solve the problem -- mostly because far, far fewer people could afford (or would be willing to foot the bill) for personal servants.
The real issue is that locals themselves are so used to being treated like crap and living under crap conditions that they don't see anything wrong with the DH system.
Requiring decent accommodations for DHs, for example, will be a hard sell so long as HK still allows HKers to live in cages, subdivided flats, etc. That's a tacit government policy since they are aware of the problem but still, year after year, aren't building sufficient public housing. Beyond that, HKers are squeezed into too-small homes so those that do want to have helpers. That's also an unwritten govt policy since commercial real estate developers are basically in competition with public housing to a certain degree and the govt-mandated square-footage-per-person numbers for public housing are tiny -- if the govt doubled those figures and, henceforth, built much larger public housing flats but charged the same rents, developers would be forced to follow suit. That would burst the bubble of the "HK is a small, small place" myth, though -- since the government would have to start building on all of the empty space that they claim doesn't exist but which is clearly visible on Google Maps/Earth from one's window when one drives around. Yup, lots of it (but far from all) is hilly/mountainous, but that doesn't mean that it can't be built upon. The problem is, of course, that the real estate developers would be minting money at a lower rate under those conditions and that's something that can't be permitted to happen.